[Elliott]

Ken,

Tell me more about the decision to upgrade. I would of loved to be around to watch to process. What did the costs run and were there modifications to the framework above the engine? Did you put in a new transmission also?

[Archived]

Ken, there is only one word to describe what you did…….Awesome!

Just guessing here, but I imagine you had to change out the tag axle and go with the six speed transmission. That makes the effort even more complex than just dropping in a new engine.

[Archived]

Congratulations Ken…

[Archived]

My 8V92 started leaking coolant around the liner o-rings into the air
box. It was just a matter of time until it entered the oil and
destroyed the engine. I decided to spend my time and money installing a
later model 4 stroke instead of repairing the 92 Series, I really never

cared for the 2 Strokes. I got real lucky and bought a complete wrecked
truck with a 14 liter Series 60 and an Eaton Ultrashift transmission for

about 10k. I know it’s had to believe but after I sold off every thing
that I
didn’t need I may have made a little money. That doesn’t mean it was free,
it’s took me almost a year to do this at 30 to 40 hours a week. Much
more difficult than I imagined.

Here’s
a link to my slide show that covers about half of my installation (I’m
working on the complete slide show). It shows the engine cradle
modifications I had to make. The only frame or structure modifications
that were necessary is adding some height to the engine access cover, a
small notch in the rear left down tube to allow some extra clearance
for the charge air cooler and I notched the tag axle for transmission
clearance when all air was dumped from the air bags, and that
modification was difficult.

http://www.youtube.com/watch?v=fybDVp_s59M

I don’t think the 6 speed Allison will fit in a Prevost before the new
design tag axle. I looked at installing the new style axle but all the
mounts to the frame are completely different. I considered building a
custom tag axle. Considering
the cost of a world transmission, the cost of building custom tag axle
and on top of that my research indicated that the 6 speed Allisons were
not reliable
past 300,000 miles and a used transmission would be all I could
afford. I decided to go with the Eaton UltraShift even before I found
the
deal on the wrecked truck. Another reason I decided to do this repower
is fuel efficiency. The automated shift, manual transmission should be
more fuel
effect than an automatic. It will be a while before I have any MPG
numbers that I trust. I can tell you at 70 MPH my RPM’s are 1400.

I hope this answers most of the questions. If anything needs further explanation let me know.

Ken

[Archived]

Ken, that is one of the most impressive posts I have read on the Prevost forums. Just the idea of taking on a complete engine and drive train change out is over the top. You really caught my attention with the 1400 rpm at 70 mph. I would make a “WAG” (wild ass guess) of fuel ecomony in 9 mph range, flat out.

How much boost at 1400-70 mph ?

I will look forward to meeting you on one of the upcoming rallies and seeing your bus.

Thank you for posting on this group.

AL

[Robert]

Thanks for the complements. I’m hoping for 10 MPG but I suspect 8 or 9 will be more likely. Even with a Variable Geometry Turbo boost pressure is still related to engine load / throttle position even at a steady RPM. I’ll check next time I’m driving it but I think I was seeing around 30 PSI at full throttle in 10th at 1400 RPM. I’ve only put about 60 miles on it so far and I seen low 40’s boost PSI if stretch out the RPM’s between shifts. I’m anxious to take it up Mount Eagle, (I’m near Nashville TN ) to see how it performs up a long grade. Speaking of Eagles, there is an Eagle Rally here in May, They say everyone is welcome. I’m planning on stopping by at least Saturday, maybe Sunday too. There is more info about the Rally on the MAK board.

Ken

[AL]

I suspect fuel mileage will be almost identical to what most of us with Series 60 engines gets. There is going to be a slight benefit to running a lower RPM at 70 MPH, but when all factors that influence mileage are considered the biggies still remain and they are speed (the headwind as we go faster takes a lot of HP), weight, hills, etc.

The transmission with more gears however does keep the engine RPM in the sweet spot so some mileage gains can be expected, but I doubt if they will be as significant as it might seem. I do know from keeping detailed records that measuring mileage and getting accurate data takes several months and lots of refueling. The variations from tank to tank can be as much as 20 to 30 gallons, but over 5000 to 10000 miles of driving the data is fairly accurate. In my coach the ProDriver is very accurate but not all coaches have a ProDriver.

Bottom line however is that is a sweet combination of engine and transmission and it is going to be far more reliable than the six speed transmissions.

[Davy]

I do have the latest Prodriver DC. I want to confirm that the real fuel mileage agrees with what the ECM is saying and I agree with you, it will take a few fill ups to determine the MPG.

Ken

[Jim/Chris]

In case you don’t know, the Ultra Shift has had LOTS of problems with electrical connectors in trucks. You may want to really verify the condition of every connection and its sealing surface before heading out on the road. The truck dealer I used to do business with was forever fixing these problems…they also exist in the Meritor Freedom line to a somewhat lesser degree. (the Freedom line has issues all it’s own over and above connectors). Many times the dealers would simply cut the connectors off and hard wire to the transmission to try to fix these issues. I don’t endorse this as it makes it harder to remove the unit if it needs repair.

Otherwise, the main box should be pretty bullet proof. You may want to practice operating in reverse too, if it works like the Freedom line does…they will sometimes surprise you by needing more throttle than one would think to get moving and then you get going too fast. We had 50 units with the Meritor in them and it was always a sore point with drivers.

[Archived]

Thanks for that information. I relocated the Transmission control unit to more accessible
location and checked the connectors, they appeared to be good quality
water proof connectors, but I will recheck them.

Thanks,

Ken

[Paul]

On our first Prevost, at around 100,000 miles the coach started locking in gear. When we were driving we would get a “do not shift” alert. When that occurred the transmission was locked in whatever gear it was in at the time. When we had to stop the engine would stall because it was still locked up in 5th. It was like stopping without stepping on the clutch.

Prevost found the 28 pin connector was corroded so the male and female portions of the connector were locked together and would not come apart. The coach had to be taken to Allison and the repair was to chisel the plugs apart and rewire the entire transmission, something that took 2 days. The corrosion was what eventually led to sending false information to the brain so the transmission was acting as it did. To the credit of Prevost and Allison the costs of the repair were borne by both companies even though the coach was out of warranty. What I learned is to separate the plug and receptacle at every service to keep the two parts from corroding together. Plugging and unplugging about every 5000 miles would evidently “wipe” any corrosion that might have developed from the pins.

It did not help that at the time we used the coach during the winter doing trade shows in the snow belt, exposing the underside of the coach to all the road salt and crud used to keep the roads clear. As Mark points out the electrical parts of the transmissions do not tolerate corrosion very well because corrosion becomes a path for or inhibits electrical signals which are very low voltage, and when that occurs the transmission will not function as intended.

[Ronald]

Here’s my last set of pictures from the engine swap. These pictures don’t cover every step but you can get a rough ideal of the things I made, rebuilt or modified when you watch both slide shows.

Ken

http://www.youtube.com/watch?v=mM2RUwzBkcc

[Archived]

Instead of starting a new thread I’m just adding to my original. Several people
asked about fuel mileage, this is what I have so far. This picture is from my
Prodriver. This is after a drive up Mt. Eagle and back on I 24. 160 miles with
the cruise set at 70 MPH when possible. There is quite a bit of stop and go
driving in this trip. I’m hoping for over 9 on a longer trip. The engine ECM
computes this estimated mileage based on distance traveled which comes from tire
size and gear ratios. The other part of the calculation is from a pre-programmed
injector size and the ECM knowing how long the injectors were open “pulse
width”. My computer MPH is correct according to my GPS and the other parameters
haven’t been altered so the ECM MPG should be close. All that being said I
wouldn’t bet a lot of money that the estimated MPG is correct, it should be
close. It will be later this summer before I can confirm the real MPG. Whatever
it is, it looks like an improvement over 5.5 with the 8V92.

Ken

[Paul]

Ken,

I just made a quick trip last week from GA to FL and back and got almost the same thing on the Pro Driver 8.64. I talked to Mango Mike returning to VA at the same time and he had just got his best fuel mileage ever. We wondered if the blend change from winter had anything to do with it. Whatever the reason, it was good, except for the price.

[Greg]

I ordered fuel for my off road fuel tank and the dealer said the price for tomorrow will be 5 cents lower than today. Lets hope the trend continues! Rick